The Redshirt Effect is a phenomenon affecting agents in the Star Trek continuum. In that continuum, those who wear a red shirt have a drastically increased mortality rate. This includes PPC agents with disguises that include red shirts. The Redshirt Effect tends to manifest as increased clumsiness, bad luck, and a general tendency to get in the way of Murphy's Law—repeatedly.
The obvious solution is not to disguise oneself as a redshirt, but this presumes one knows about the existence of the Redshirt Effect and can find a disguise which does not include a red shirt.